Abstract: The KrF excimer laser was studied here. The large area uniform glow discharge was realized by using compact Chang electrode combined ultraviolet spark pre-ionization, and to provide high-voltage discharge with high rising edge, the laser described here used LC inversion and one-stage magnetic switch in excitation circuit. The influence of the laser pulse energy by the work gas content was studied, and in volume ratio of F2/He∶Kr∶Ne = 1.97∶3.18∶94.85 gas mixture at the total gas pressure of 330 kPa, the cross section of the output beam was 30 mm14 mm at 27 kV charging voltage. A maximum output energy of 738 mJ was obtained. And the maximal overall efficiency was up to 2.0% with the charging voltage up to 23 kV.